http://www.straightdope.com/classics/a2_426.html
My brother actually broke his penis. The other female members of my family all have an idea of how this happened. BUT the official version is that while waking suddenly in the middle of a “dream” because the alarm went off. My brother jumped out of bed and got his penis cought in the bedcovers. Snapping it. He had an emergency operation that lasted nearly 3 hours.
He was told to wait 3-4 months before trying to have sex. Further rupturs could cause permenant damage.
This does happen. And yes all ladies laugh at the thought 
Yikes! I for one wince ever so slightly upon hearing about this…ouch!!!
This is one of those things that give me great pause. Ever since I read about it (in, I think, Everything you Ever wanted yo know about Sex, etc.), it has haunted me. This could happen to you!. If anything can put a damper on sex, this is it.
Cruel, ladies. Think this way and you’ll get a lot less sympathy from guys about things like PMS. Then who’s gonna bring you those therapeutic chocolates?
I don’t get any sympathy for PMS. All the guys at work think I enjoy being bedridden with severe nausea-inducing cramps because I get to skip a day of work.
If their penises break <snicker> I’ll show them as much sympathy.
Yeah, but I thank my lucky stars that my penis doesn’t break 4-7 days out of the month. Woo-boy.
Friend of mine told me to search on Straight Dope to see if a penis is supposed to pop like a knuckle…didn’t find anything…ouch.